Birefringent interference polarization
First Claim
1. A broadband birefringent reflective polarizer comprising a bireffingent material arranged in optical repeating units disposed spatially along a thickness axis of the reflective polarizer, each optical repeating unit having a corresponding wavelength for which light of a first polarization is substantially reflected while light of a second polarization is substantially transmitted, the optical repeating units being graded along the thickness axis of the reflective polarizer such that a broadband of incident light is polarized by the reflective polarizer.
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Accused Products
Abstract
A birefringent interference polarizer which may be fabricated from readily available materials using established coextrusion techniques is provided. The polarizer has a level of light absorption near zero and can be fabricated to polarize and reflect light of specific wavelengths while transmitting light of other wavelengths. The polarizer includes multiple alternating oriented layers of at least first and second polymeric materials having respective nonzero stress optical coefficients which are sufficiently different to produce a refractive index mismatch between the first and second polymeric materials in a first plane which is different from the refractive index mismatch between the first and second polymeric materials in a second plane normal to the first plane. The refractive index mismatch in the first plane is preferably at least 0.03.
128 Citations
16 Claims
- 1. A broadband birefringent reflective polarizer comprising a bireffingent material arranged in optical repeating units disposed spatially along a thickness axis of the reflective polarizer, each optical repeating unit having a corresponding wavelength for which light of a first polarization is substantially reflected while light of a second polarization is substantially transmitted, the optical repeating units being graded along the thickness axis of the reflective polarizer such that a broadband of incident light is polarized by the reflective polarizer.
- 5. A broadband birefringent reflective polarizer comprising a birefringent material arranged in optical repeating units disposed spatially along a thickness axis of the reflective polarizer, a dimension of the repeating units forming an optical thickness gradient along the thickness axis such that a broadband of light of a first polarization encounters changes in refractive indices as it propagates in the reflective polarizer and is substantially reflected while a broadband of light of a second polarization encounters substantially uniform refractive indices as it propagates through the reflective polarizer and is substantially transmitted.
- 10. A broadband birefringent reflective polarizer comprising a birefringent material arranged in optical repeating units disposed spatially along a thickness axis of the reflective polarizer and having a graded optical thickness along the thickness axis such that a broadband of light of a first polarization encounters changes in refractive indices as it propagates in the reflective polarizer and is substantially reflected while a broadband of light of a second polarization encounters substantially uniform refractive indices as it propagates through the reflective polarizer and is substantially transmitted.
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15. A broadband birefringent reflective polarizer comprising a birefringent material arranged in optical repeating units disposed spatially along a thickness axis of the reflective polarizer, a dimension of the repeating unit forming an optical thickness gradient along the thickness axis such that a broadband of light of a first polarization is substantially reflected while a broadband of light of a second polarization is substantially transmitted.
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16. A broadband birefringent reflective polarizer comprising a birefringent material arranged in optical repeating units arranged along a thickness axis of the reflective polarizer and having a graded optical thickness along the thickness axis such that a broadband of light of a first polarization is substantially reflected while a broadband of light of a second polarization is substantially transmitted.
Specification